The WS specifications related to Transactions (WS-Coordination, WS-AtomicTransaction and WS-BusinessActivity) http://msdn.microsoft.com/webservices/webservices/understanding/specs/default.aspx?pull=/library/en-us/dnglobspec/html/wsatspecindex.asp.

XA transaction specification

http://www.opengroup.org/onlinepubs/009680699/toc.pdf

TIP transactions specification

http://www.ietf.org/rfc/rfc2371.txt

OLE Transactions Model
http://windowssdk.msdn.microsoft.com/library/en-us/Mts/rmguidetug_7pd8.asp?frame=true